Novel Computational Chemistry Infrastructure for Simulating Astatide in Water: From Basis Sets to Force Fields Using...

Area of Science:

• Computational Chemistry
• Relativistic Quantum Chemistry
• Chemical Physics

Background:

• Astatine (At) is the heaviest naturally occurring halogen, with At-211 showing medical potential.
• Simulating heavy elements requires accounting for strong relativistic effects.
• Accurate computational models are crucial for understanding and utilizing these elements.

Purpose of the Study:

• To propose a new infrastructure for large-scale computational models of heavy elements with strong relativistic effects.
• To develop an accurate force field for the astatine anion (At-) in water.
• To establish a framework for creating polarization-consistent basis sets for relativistic density functional theory (DFT).

Main Methods:

• Developed novel basis sets for relativistic DFT using particle swarm optimization.
• Extended the polarization-consistent basis set idea to heavy elements.
• Performed relativistic DFT calculations and validated against coupled cluster with singles, doubles, and triples (CCSD(T)) results.
• Computed force field parameters, radial distribution functions, diffusion coefficients, and hydration energies for At- in water.

Main Results:

• Designed and validated new basis sets for relativistic DFT, minimizing basis set error.
• Elucidated significant differences between At- and I- in halide-water interactions, including force field parameters and hydration energies.
• Demonstrated the importance of accounting for relativistic effects, such as spin-orbit interaction, in heavy element simulations.

Conclusions:

• Established a framework for systematic development of basis sets for relativistic DFT and accurate force fields for molecular dynamics.
• The new infrastructure enables large-scale simulations of complex systems involving heavy elements, including actinides and superheavy elements.
• This work paves the way for improved computational studies in nuclear medicine and materials science involving heavy elements.